﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.SS.Util;
using System.Web;

namespace Utilities
{
    /// <summary>
    ///ExsclHelper 的摘要说明
    /// </summary>
    public class ExclHelper
    {
        public ExclHelper()
        {
            
        }
        /// <summary>
        /// DataTable导出到Excel的MemoryStream
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <returns></returns>
        public static MemoryStream Export(DataTable dtSource, string strHeaderText)
        {
            //创建一个Excel文件
            HSSFWorkbook workbook = new HSSFWorkbook();
            //创建一个工作表
            ISheet sheet = workbook.CreateSheet();

            //#region 右击文件 属性信息 (添加上打开Excel说有危险....)
            //{
            //    DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            //    dsi.Company = "";
            //    workbook.DocumentSummaryInformation = dsi;

            //     SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            //     si.Author = "备注"; //填加xls文件备注信息
            //     si.ApplicationName = "文件创建程序信息"; //填加xls文件创建程序信息
            //     si.LastAuthor = "文件最后保存者信息"; //填加xls文件最后保存者信息
            //     si.Comments = "文件作者信息"; //填加xls文件作者信息
            //     si.Title = "文件标题信息"; //填加xls文件标题信息
            //     si.Subject = "文件主题信息";//填加文件主题信息
            //     si.CreateDateTime = DateTime.Now;
            //     workbook.SummaryInformation = si;
            // }
            // #endregion

            ICellStyle dateStyle = workbook.CreateCellStyle();
            IDataFormat format = workbook.CreateDataFormat();
            dateStyle.DataFormat = format.GetFormat("yyyy-MM-dd");

            //取得列宽
            int[] arrColWidth = new int[dtSource.Columns.Count];
            foreach (DataColumn item in dtSource.Columns)
            {
                arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
            }
            for (int i = 0; i < dtSource.Rows.Count; i++)
            {
                for (int j = 0; j < dtSource.Columns.Count; j++)
                {
                    int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                    if (intTemp > arrColWidth[j])
                    {
                        arrColWidth[j] = intTemp;
                    }
                }
            }

            int rowIndex = 0;

            #region 表头及样式(表的标题，合并单元格显示)
            if (strHeaderText != "")
            {
                //行
                IRow headerRow = sheet.CreateRow(rowIndex);
                headerRow.HeightInPoints = 25;
                headerRow.CreateCell(0).SetCellValue(strHeaderText);

                ICellStyle headStyle = workbook.CreateCellStyle();
                headStyle.Alignment = HorizontalAlignment.CENTER;
                IFont font = workbook.CreateFont();
                font.FontHeightInPoints = 20;
                font.Boldweight = 700;
                headStyle.SetFont(font);

                headerRow.GetCell(0).CellStyle = headStyle;
                sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, dtSource.Columns.Count - 1));
                //headerRow.Dispose();
                rowIndex++;
            }
            #endregion

            #region 列头及样式
            {
                //行
                IRow headerRow = sheet.CreateRow(rowIndex);


                ICellStyle headStyle = workbook.CreateCellStyle();
                headStyle.Alignment = HorizontalAlignment.CENTER;
                IFont font = workbook.CreateFont();
                font.FontHeightInPoints = 10;
                font.Boldweight = 700;
                headStyle.SetFont(font);


                foreach (DataColumn column in dtSource.Columns)
                {
                    headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                    headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                    //设置列宽
                    sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);

                }
                //headerRow.Dispose();
                rowIndex++;
            }
            #endregion

            foreach (DataRow row in dtSource.Rows)
            {
                #region 新建表，填充表头，填充列头，样式
                if (rowIndex == 65535)
                {
                    if (rowIndex != 0)
                    {
                        sheet = workbook.CreateSheet();
                    }

                    #region 表头及样式(表的标题，合并单元格显示)
                    if (strHeaderText != "")
                    {
                        //行
                        IRow headerRow = sheet.CreateRow(rowIndex);
                        headerRow.HeightInPoints = 25;
                        headerRow.CreateCell(0).SetCellValue(strHeaderText);

                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = 20;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);

                        headerRow.GetCell(0).CellStyle = headStyle;
                        sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, dtSource.Columns.Count - 1));
                        //headerRow.Dispose();
                        rowIndex++;
                    }
                    #endregion


                    #region 列头及样式
                    {
                        //行
                        IRow headerRow = sheet.CreateRow(rowIndex);


                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = 10;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);


                        foreach (DataColumn column in dtSource.Columns)
                        {
                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            //设置列宽
                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);

                        }
                        //headerRow.Dispose();
                        rowIndex++;
                    }
                    #endregion


                }
                #endregion


                #region 填充内容
                IRow dataRow = sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dtSource.Columns)
                {
                    ICell newCell = dataRow.CreateCell(column.Ordinal);

                    string drValue = row[column].ToString();

                    switch (column.DataType.ToString())
                    {
                        case "System.String"://字符串类型
                            newCell.SetCellValue(drValue);
                            break;
                        case "System.DateTime"://日期类型
                            DateTime dateV;
                            DateTime.TryParse(drValue, out dateV);
                            newCell.SetCellValue(dateV);

                            newCell.CellStyle = dateStyle;//格式化显示
                            break;
                        case "System.Boolean"://布尔型
                            bool boolV = false;
                            bool.TryParse(drValue, out boolV);
                            newCell.SetCellValue(boolV);
                            break;
                        case "System.Int16"://整型
                        case "System.Int32":
                        case "System.Int64":
                        case "System.Byte":
                            int intV = 0;
                            int.TryParse(drValue, out intV);
                            newCell.SetCellValue(intV);
                            break;
                        case "System.Decimal"://浮点型
                        case "System.Double":
                            double doubV = 0;
                            double.TryParse(drValue, out doubV);
                            newCell.SetCellValue(doubV);
                            break;
                        case "System.DBNull"://空值处理
                            newCell.SetCellValue("");
                            break;
                        default:
                            newCell.SetCellValue("");
                            break;
                    }

                }
                //dataRow.Dispose();
                #endregion

                rowIndex++;
            }
            //#region 追加的行
            //HSSFRow dataRowavg = sheet.CreateRow(rowIndex);
            //dataRowavg.CreateCell(0).SetCellValue("平均");
            //int aai = 3;
            //if (strHeaderText=="")
            //{
            //    aai = 2;
            //}
            ////平均值计算
            //dataRowavg.CreateCell(1).SetCellFormula("AVERAGE(B"+aai+":B" + Convert.ToString(rowIndex) + ")");
            //dataRowavg.CreateCell(2).SetCellFormula("AVERAGE(C"+aai+":C" + Convert.ToString(rowIndex) + ")");
            //dataRowavg.CreateCell(3).SetCellFormula("AVERAGE(D"+aai+":D" + Convert.ToString(rowIndex) + ")");
            //dataRowavg.CreateCell(4).SetCellFormula("AVERAGE(E"+aai+":E" + Convert.ToString(rowIndex) + ")");
            //dataRowavg.CreateCell(5).SetCellFormula("AVERAGE(F"+aai+":F" + Convert.ToString(rowIndex) + ")");
            //HSSFRow bootdataRow = sheet.CreateRow(rowIndex + 1);
            //bootdataRow.CreateCell(0).SetCellValue("总计");
            ////求和计算
            //bootdataRow.CreateCell(1).SetCellFormula("sum(B"+aai+":B" + Convert.ToString(rowIndex) + ")");
            //bootdataRow.CreateCell(2).SetCellFormula("sum(C"+aai+":C" + Convert.ToString(rowIndex) + ")");
            //bootdataRow.CreateCell(3).SetCellFormula("sum(D"+aai+":D" + Convert.ToString(rowIndex) + ")");
            //bootdataRow.CreateCell(4).SetCellFormula("sum(E"+aai+":E" + Convert.ToString(rowIndex) + ")");
            //bootdataRow.CreateCell(5).SetCellFormula("sum(F"+aai+":F" + Convert.ToString(rowIndex) + ")"); 
            //#endregion

            MemoryStream ms = new MemoryStream();
            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;
            return ms;
        }
        /// <summary>
        /// Web导出下载
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <param name="strFileName">文件名</param>
        public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName)
        {

            HttpContext curContext = HttpContext.Current;

            // 设置编码和附件格式
            curContext.Response.ContentType = "application/vnd.ms-excel";
            curContext.Response.ContentEncoding = Encoding.UTF8;
            curContext.Response.Charset = "";
            curContext.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));
            curContext.Response.BinaryWrite(Export(dtSource, strHeaderText).GetBuffer());
            curContext.Response.End();
        }
        /// <summary>
        /// 输出文件流
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <param name="strFileName">文件名</param>
        public static Stream ExportStream(DataTable dtSource, string strHeaderText, string strFileName)
        {
            return Export(dtSource, strHeaderText);
        }

        /// <summary>由Excel导入DataTable</summary>  
        /// <param name="excelFileStream">Excel文件流</param> 
        /// <param name="headerRowIndex">Excel表头行索引(从0开始)</param> 
        /// <returns>DataTable</returns>   
        public static DataTable ImportDataTableFromExcel(Stream excelFileStream, int headerRowIndex)
        {
            //根据路径通过已存在的excel来创建HSSFWorkbook，即整个excel文档
            IWorkbook workbook = new HSSFWorkbook(excelFileStream);
            //获取excel的第一个sheet
            ISheet sheet = workbook.GetSheetAt(0);
            //声明表
            DataTable table = new DataTable();
            //获取sheet的首行
            IRow headerRow = sheet.GetRow(headerRowIndex);
            //一行最后一个方格的编号 即总的列数(LastCellNum不是从0开始？？，FirstCellNum是从0开始)
            int cellCount = headerRow.LastCellNum;
            //获取首行
            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
                if (headerRow.GetCell(i) == null || headerRow.GetCell(i).StringCellValue.Trim() == "")
                {
                    // 如果遇到第一个空列，则不再继续向后读取    
                    cellCount = i = 1;
                    break;
                }
                DataColumn column = new DataColumn(strType(headerRow.GetCell(i)));
                //添加列
                table.Columns.Add(column);
            }
            ////最后一列的标号  即总的行数
            //int rowCount = sheet.LastRowNum;
            //while (sheet.GetRowEnumerator().MoveNext())
            //{

            //}
            //添加内容,从表头行的下一行开始(sheet.LastRowNum从0开始？？)
            for (int i = (headerRowIndex + 1); i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                //if (row == null || row.GetCell(0) == null || row.GetCell(0).ToString().Trim() == "")
                //{
                //    // 如果遇到第一个空行，则不再继续向后读取        
                //    break;
                //}
                if (row != null) // 为空行不添加
                {
                    DataRow dataRow = table.NewRow();
                    for (int j = row.FirstCellNum; j < cellCount; j++)
                    {

                        dataRow[j] = strType(row.GetCell(j));
                    }
                    table.Rows.Add(dataRow);
                }
                else
                {
                    DataRow dataRow = table.NewRow();
                    table.Rows.Add(dataRow);
                }
            }
            excelFileStream.Close();
            workbook = null;
            sheet = null;
            return table;
        }

        public static string strType(ICell cell)
        {
            if (cell == null)
            {
                return "";
            }
            switch (cell.CellType)
            {
                case CellType.BLANK:
                    return "[null]";
                case CellType.BOOLEAN:
                    return cell.BooleanCellValue.ToString();
                case CellType.NUMERIC:
                    return cell.ToString();
                case CellType.STRING:
                    return cell.StringCellValue;
                case CellType.ERROR:
                    return cell.ErrorCellValue.ToString();
                case CellType.FORMULA:
                    return cell.NumericCellValue.ToString();
                default:
                    return "=" + cell.CellFormula;
            }
        }

    }
}
